One of my hives suddenly went quiet. I checked they have lots of honey still. Early morning it was very cold so I looked through the entrance and noticed this Hard brown crusty stuff that is clumpy and touches the bottom board. I checked another hive and see a similar pattern of sealing all the way to the bottom of the hive. Any ideas?
A photo would help. Sounds like propolis, but hard to know. Have you put your ear to the hive? Is it still alive?
I agree with @Dawn_SD and would need a photo to see what you are asking about. How long ago did you have the brood frames out doing an inspection? Just a thought that the bees may have built comb down to the base board from the bottom of the frames to increase the brood area but without a pic that is just a first thought.
By looking thru the entrance how do you know what you are seeing is hard and crusty?
bees often build comb that hangs off the bottom of the frames to nearly touch the floor of the hive. Some hives have a larger space between the bottom of the frames and the floor and bees build more in such hives, this could possibly be what you are seeing? It’s likely the bees have abandoned that comb over winter- it’s more of a spring thing for them.